# Biogeography of Virioplankton Abundance and Subcluster Patterns in the Northwest Pacific: A Large‐Scale Perspective

## TL;DR

This study explores the distribution and diversity of marine viruses in the Northwest Pacific, revealing new patterns linked to environmental factors.

## Contribution

The study introduces a high-resolution method to detect viral subclusters and their environmental drivers in marine ecosystems.

## Key findings

- Four consistent viral subclusters were identified across oceanic and coastal waters, with a fifth found only in the Yellow Sea.
- Environmental factors like temperature and chlorophyll strongly influence viral community structures.
- The Luzon Strait shows distinct viral communities despite similar abundance levels, highlighting hidden diversity.

## Abstract

Marine virioplankton, the most abundant biological entities in the ocean, play essential roles in microbial ecology and biogeochemical cycling. This study investigates their biogeography in the Northwest Pacific using enhanced‐resolution flow cytometry and phenotypic diversity analyses. By resolving four consistent viral subclusters across oceanic and coastal waters and detecting a fifth subcluster in the Yellow Sea, we revealed previously unrecognized patterns of viral community structures. Viral abundances ranged from 3.69 × 10⁶ to 17.09 × 10⁶ particles/mL, showing clear coastal‐oceanic differentiation. Environmental gradients, particularly temperature, chlorophyll, and picoplankton abundance, emerged as the primary drivers of virioplankton community structure. These findings underscored the tight coupling between viral populations and their microbial hosts across contrasting marine environments. Phenotypic diversity analysis revealed distinct viral communities in the Luzon Strait, despite comparable abundance patterns to adjacent regions, demonstrating the method's sensitivity in detecting subtle community shifts. This study advances understanding of marine viral biogeography and introduces a robust framework for investigating viral community dynamics. The approach enables high‐throughput screening across large spatial scales while maintaining sensitivity to fine‐scale community variations, offering new possibilities for monitoring viral responses to environmental change in marine ecosystems.

Enhanced‐resolution flow cytometry combined with phenotypic diversity analysis reveals four consistent viral subclusters and a fifth restricted to the Yellow Sea across the Northwest Pacific. These results identify a cryptic diversity hotspot in the Luzon Strait and demonstrate how environmental and biological gradients shape large‐scale patterns in marine viral biogeography.